标题： 不同Ia型超新星前身星对银河系化学演化的影响 显示英文标题

标题： The Effect of Different Type Ia Supernova Progenitors on Galactic Chemical Evolution

摘要： 我们的目标是展示关于Ia型超新星前身的不同假设如何影响银河系的化学演化。我们将不同的Ia型超新星前身模型（通过它们的时间延迟分布来识别）纳入一个非常详细的银河系化学演化模型中，该模型追踪了几种化学元素的演化。 我们测试了单简并星和双简并星模型作为Ia型超新星的前身，并且还测试了一些基于时间延迟分布差异的更经验性的模型。我们发现，假设单简并星或双简并星情景在预测的[O/Fe]与[Fe/H]关系上产生的差异可以忽略不计。 另一方面，假设50%的Ia型超新星是即时爆炸的（在前1亿年内），或者最大Ia型超新星率在恒星形成开始后3-4吉年时达到（这是几位作者提出的），会对[O/Fe]趋势产生更显著的影响。然而，考虑到观测数据中仍然存在的差异，没有任何模型可以仅仅基于[O/Fe]比率被排除。 另一方面，当不同模型的预测与G矮星金属丰度分布进行比较时，那些假设极少数即时Ia型超新星的情景可以被排除。包括单简并星或双简并星情景并且有10-13%即时Ia型超新星比例的模型，其结果与观测结果非常吻合。超过30%的即时Ia型超新星比例会恶化与观测结果的一致性，同样地，如果不允许有任何即时Ia型超新星的话也会出现相同的情况。 特别是，两种经验性的Ia型超新星前身模型可以被排除：一种是没有即时Ia型超新星的模型，另一种是假设延迟时间分布遵循t^{-0.5}的模型。 显示英文摘要

摘要： Our aim is to show how different hypotheses about Type Ia supernova progenitors can affect Galactic chemical evolution. We include different Type Ia SN progenitor models, identified by their distribution of time delays, in a very detailed chemical evolution model for the Milky Way which follows the evolution of several chemical species. We test the single degenerate and the double degenerate models for supernova Ia progenitors, as well as other more empirical models based on differences in the time delay distributions. We find that assuming the single degenerate or the double degenerate scenario produces negligible differences in the predicted [O/Fe] vs. [Fe/H] relation. On the other hand, assuming a percentage of prompt (exploding in the first 100 Myr) Type Ia supernovae of 50%, or that the maximum Type Ia rate is reached after 3-4 Gyr from the beginning of star formation, as suggested by several authors, produces more noticeable effects on the [O/Fe] trend. However, given the spread still existing in the observational data no model can be firmly excluded on the basis of only the [O/Fe] ratios. On the other hand, when the predictions of the different models are compared with the G-dwarf metallicity distribution, the scenarios with very few prompt Type Ia supernovae can be excluded. Models including the single degenerate or double degenerate scenario with a percentage of 10-13% of prompt Type Ia supernovae produce results in very good agreement with the observations. A fraction of prompt Type Ia supernovae larger than 30% worsens the agreement with observations and the same occurs if no prompt Type Ia supernovae are allowed. In particular, two empirical models for the Type Ia SN progenitors can be excluded: the one without prompt Type Ia supernovae and the one assuming delay time distribution going like t^{-0.5}.